Hot-air furnace



(No Model 2 Sheets-Sheet 1.

J. EVANS. HOT AIR FURNACE.

No. 496,193. a Patented Apr. 25, 1893.

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(No Model.) 2 SheetsSheet 2. J. EVANS. HOT AIR FURNACE.

No. 496,193. Patented Apr. 25, 1893.

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UNITED STATES PATENT OFFICE.

JOHN EVANS, OF PHILADELPHIA, PENNSYLVANIA.

HOT-AIR FURNACE.

SPECIFICATION forming part of Letters Patent No. 496,193, dated April25, 1893.

Application filed May 27, 1892. Serial No. 434,644- (No model.)

.To all whom it may concern: 7

Be it known that I, JOHN EVANS, a citizen of the United States, residingin the city of Philadelphia, in the county of Philadelphia and State ofPennsylvania, have invented certain new and useful Improvements in Hot-Air Furnaces, of which the following is a specification.

My present invention relates to hot airfurnaces in which the heatradiated from the combustion chamber and its accessories is employed orutilized for warming the incoming cold air preparatory to its finalheating and delivery.

The principal object of my present invention is to provide a simple,durable, comparatively inexpensive and efficient hot air furnace; and tothis end my invention consists in the improvements hereinafter describedand particularly pointed out in the claims.

The nature, objects and general scope of my invention will be more fullyunderstood from the following description taken in connection with theaccompanying drawings forming part hereof; and in which Figure 1, is atop or plan view, partly in section on the line 1-1, of Fig. 3, of a hotair furnace embodying features of my invention. Fig. 2, is a sideelevation thereof. Fig. 3, is a section taken on the line 33, of Fig. 1.Fig. 4:, is a view partly in section and partly in elevation of thefurnace taken on the line 4-4, of Fig. 5, showing the funnel shape ortapering casting with its spider consisting of arms radiating inwardtherefrom. Fig. 5, is a sectional elevation of the lower portion of thefurnace taken on the line 5-5, of Fig. 4, showing the funnel shape ortapering and flaring casting mounted on the baseplate of the furnace andprovided with a spider having inclined or beveled walls; and Fig. 6, isa view partly in section and partly in elevation of so much of thefurnace as is illustrated in Fig. 5, in order to expose to view theexterior surface of the funnel-shape or tapering and flaring castingconnected with the base-plate of the furnace of my invention.

In the drawings a, is the exterior shell of the furnace within which allthe internal fiues, passages, channels and accessories are contained.1), is a similar internal'casing located within the exterior shell a.This casing 1), may be made double, or in other words, jacketed so as toafford a passage 0', for air to pass in order to prevent cold air fromimpinging directly upon the hotter or interior member of the doublecasing.

The shell a, and the casing 19, are not concentric. The center of thecasing 11, is located between the center of the shell a, and the frontof the furnace, as shown more particularly in Fig. l. The space 0,between the exterior shell to, and the casing b, is wider at the rearthan at the front of the furnace to accommodate the flue d, thatconducts the products of combustion to the smoke off-take e, as fullyillustrated in Fig. 2.

f, is a plate supported upon the top of the external shell a, andprovided with air inlets -or openings f, and with an aperture f throughwhich the fiue d, passes.

g, is a dome or hood fitted over a central aperture provided in theplate f.

h, is a hot air receiving chamber supported on top of the casing b, bymeans of a fillet h, in order to prevent the cap from closing theopenings f.

The space 1', included by the plate f, dome or hood g, and receivingchamber h, comprises the hot-air reservoir in which the previouslywarmed air is thoroughly heated and from which the same is distributedby means of pipes or flues z" and i j, is a funnel-shaped or taperingand flaring casting mounted on the base-plate 717, of the furnaceprovided with a spiderj', and with inclined or beveled circular wallsjfor purposes to be presently more fully explained. In the presentinstance this spider j, comprises arms radiating inward from thecastingand supporting at their extremities a ring or annulus.

Within the furnace is provided an open top tubular housing forming thewall of the combustion chamber Z, fire-pot or chamber Z and ash-pit orchamber Z This housing Z,is supported upon the spider j at some distancefrom the base-plate 7c, and extends upward to within a short distancefrom the top plate f, so that the housing Z, extends from substantiallythe top to the bottom of the internal portion of the furnace.

m, are air-pipes extending through the plate 'f, and-through theinclined or beveled annular wall or plate 9' so that these pipes m,communicate with the hot air reservoir 1', and with an air supplyreservoir n, located at or about the bottom of the furnace and includedor bounded by the shell (1, base It and exterior surface or wall of thecasting j.

0, is a rectangular or annular chamber or conduit extending from theexterior surface a, of the furnace and communicating with the fiue oroil-take d, and alfords a channel for the passage of the products ofcombustion, as well as a receptacle for soot or other extraneous matter.

p, is a hinged door located at the outerend of the chamber 0, andadapted for the reception of a hoe or other scraping appliance for thepurpose of removing dust or other extraneous matter from the chamber orconduit 0, and to permit of the ingress of air therein for regulating orchecking the draft ad libitum of the furnace.

r, is a door connected with an internal chute r in communication withthe combustion chamber Z, and fire-pot or chamber Z. This door 1'aifords the means for permitting of the introduction of fuel into thetire-pot mass above the grate s, interposed between the fire-pot Z, andash-pit Z 0", is a door provided with an internal chute r communicatingwith the ash-pit Z and affording the means for removal of ashes, clinkerand other extraneous matter from said pitor chamber.

The ash pit or chamber Z is preferably provided with a false orremovable bottom 25, which normally serves to support ash or otherextraneous matter from time to time deposited therein and which bottomwhen removed permits of access being had to the interior of the lowerpart of the furnace for cleaning or removing collecting soot or othermatter into the chamber or conduit 0. The curved walls of the ash-pitmay be provided with one or more doors it, through which access may behad for removing dust, soot or other matter that may adhere to thesurface of the air pipes m, or to any of the otherinternal parts of thefurnace around or about the'ash-chamber 1*. However, very little dust orsoot can accumulate on and around the pipes m, because such dust or sootor other matter falls upon the inclined wall j, or beveled collector j,and by gravity is discharged from its sloping surfaces into the chamberor conduit 0, from which it may be readily removed by means of ascraping device by raising the door 10. It may be remarked that dust orsoot falling from the flue d, also collects in the chamber or conduit 0,and from which it maybe readily removed in the manner hereinabove fullyexplained. It will be observed that substantially all dust, soot orother extraneous matter given off by escaping products of combustioncollects in the chamber or conduit 0, and may be readily removed fromthe furnace. By these means the internal areaor parts of the furnace maybe kept perfectly free from dust or other extraneous matter, so that theefficiency of the furnace is materially increased and is never impairedeven when the furnace has been in use for a considerable length of time.

The dish-shaped extraneous matter collecting device j, it will beobserved serves a twofold purpose, that as before stated and as adirector of the smoke or of the gaseous products of combustion in theirdownward course from the top of the combustion chamber l along the wholeextent or surface of the housing constituting the wall of the chambersl, l and Z to the chamber or conduit 0, and through the same to thevertical flue d, from whence they pass outward through the offtake 6,thereof, into the open air, whereby it will be observed by specialreference to Fig. 3, that the heat of the escaping products ofcombustion is thoroughly or completely imparted by radiation to the downWard currents or volumes of incoming or cold air as well as to theupward currents in their ascent through v the series of pipes disposedadjacent to the annular passage or space through which the escapingproducts of combustion are drawn before reaching the off-take 01, itselbow extension e, and escaping into the open air.

The mode of operation of the hereinabove described furnace is asfollowsz-T'he products of combustion escape from the combustion chamber1, around and in a downward direction through the annular chamber orspace included between the housing of the combustion chamber Z, andcasing 12, through the funnel-shaped soot collecting and directingdevice 3', into the chamber or conduit 0, and then upward through theflue d, tothe off-take e, as is indicated by the arrows numbered l, inFig. 3. The cold air enters the openings f provided in the top plate f,mounted on the top of the furnace and descends through the passage orflue c, to the air supply reservoir n, at or near the bottom of thefurnace and to the interior annular-space c, Fig. 1, of the doublecasing c, and then ascends through the pipes m, and space 0', to the hotair'reservoir i, as is indicated by the arrows numbered 2, in'Fig. 3.Thus both the air and gaseous products of combustion traverse the lengthof the furnace once in a downward direction and once in an upwarddirection. The products of combustion. in traversing the exteriorsurface of the housing Z, are super-heated by radiation from thecombustion, fire-pot and ash-pit chambers, and

these'super-heated products of combustion impart their heat to the pipesm, double casing b, funnel'shaped casting j, rectangular chamber 0, andflue d, andescape in a comparatively cool state or condition into andingj, and it is similarly warmed by passing through the pipes m, andspace 0', to the hot air reservoir 1', where it is super-heatedpreparatory to its distribution through the outlets i and '5 In thelatter reservoir it will be understood that the same is heated bydirect' radiation from the fire and preparatory to its distributionthrough the above mentioned lines.

The draft of the furnace may be regulated or diminished ad libitum bythe opening of the door 19, that is to say, when air is admitted to theflue d, the latter is cooled and the normal draft of the furnace isconsequently diminished or checked. Moreover is this advantageous,especially when it is desired to remove soot or other extraneous matterfrom the chamber or conduit 0, Without drawing the fire-bed for thatpurpose.

It will be obvious to those skilled in the art to which my inventionappertains that as to minor details modifications maybe made withoutdeparting from the spirit of the invention, and hence I do not wish tolimit myself to the precise construction and arrangement of the parts ashereinbefore explained, for example, the doors in the ash-pit wall maybe omitted, if preferred, or they may occupy a different position tothat shown in the drawings without departing from the spirit of theinvention.

Having therefore described the nature and general and specific objectsof my invention, what I claim as new, and desire to secure by LettersPatent, is-

1. A hot air furnace provided with an exterior shell, a plate providedwith air inlet apertures and mounted on said shell, a hot air reservoirsupported by said plate, air channels or chambers communicating with theapertures of said plate and leading to an air supply reservoir in thebottom of the furnace, an internally supported casing forming'the wallof a combustion chamber, fire-pot and ash-pit, an internal smoke tlueand dust-collector located beneath said ash-pit, and air pipes directlyconnecting said top and bottom reservoirs with each other, substantiallyas and for the purposes set forth.

2. A hot air furnace provided with a top plate having peripheralopenings therein, an internally supported casing forming the wall of acombustion chamber, fire-pot and ashpit, a tapering collecting chamberand directing device located beneath said casing and communicating withan internal conduit or chamber, and an internal vertical pipe or flueextending through one of the openings of the top-plate, substantially asand for the purposes set forth.

3. A hot air furnace provided with an exterior shell, a top-plate havinga flanged periphery engaging said shell and having openings therein, aninternal smoke or product of combustion flue extending through one ofthe openings in said plate, means for conducting the products ofcombustion from an internally supported casing forming the wall of acombustion chamber, fire-pot and ash-pit in a downward direction throughthe interior of the furnace and beneath the ash-pit into an internalconduit or chamber in direct communication with said smoke and gaseousproduct flue, and an opening in the exterior shell closed by a dooradapted to check the draft of the furnace, substantially as and for thepurposes set forth.

at. A hot air furnace provided with a hot air reservoir at the topsupported by an exterior shell and a funnel-shaped perforating casting,as described, supported beneath the internal ash-pit and with theexterior shell forming the wall of an air reservoir at the bottom, airpipes connecting the reservoirs with each other, and a combustionchamber, fire-pot and ash-pit located one above the other and thecombustion chamber in communication with the interior of said casting,substantially as and for the purposes set forth.

5. A hot air furnace provided with an open top internal casingcomprising a combustion chamber, fire-pot and an ash-pit, means forsupporting said internal casing, a pot-shaped casting located beneaththe ash-pit, a casing supported upon said casting and surrounding theinternal casing for drawing or conducting the products of combustiondownward around the interior casing and through the pot-shaped castingto the base plate of the furnace, substantially as and for the purposesset forth.

6. A hot air furnace provided with an exterior shell, a funnel-shapedcasting supported on the base plate of the furnace and forming togetherwith the shell the wall of an air supply reservoir, an interior casingeccentric to the shell and supported by the periphery of the casting, ahot air reservoir at the top of the furnace, air pipes connecting thereservoirs with each other, an open top housing concentric with thecasing and supported above the casting and constituting the ashpit,fire-pot and combustion chamber and a smoke flue leading from theinterior of the casting through the interior of the furnace to the topthereof, substantially as and for the purposes set forth.

7. A hot air furnace provided with a funnel-shaped casting carrying aspider-frame, an exterior shell constituting together with the castingan annular air supply reservoir, an open top housing carried by thespiderframe and provided with an ash-pit, fire-pot and combustionchamber, and an internal casing carried by the funnel-shaped casting andadapted to direct the products of combustion through the casting,substantially as and for the purposes set forth.

8. A hot air furnace provided with a funnel-shaped casting having aspider-frame,

' an exterior shell forming with the casting the walls of an annular airsupply chamber, an

ash-pit supported in position by said spiderframe, an interior casingforming with the wall of the combustion chamber a passage for deflectingthe gaseous products of coinbustion around and beneath the ash-pitprovided with openings through which access may be had to the interiorof the gaseous product passage, substantially as and for the purposesset forth.

9. A hot air furnace provided with an internal funnel-shaped perforatedcasting having a spider-frame, an open top internal casing supported bysaid casting, pipes located around said casing and extending through thewall of said casting, an internal shell supported by said casting fordeflecting the gaseous products of combustion to a flue or conduitconnected directly with an internal vertical off-take and an ash-pit inthe internal casing having doors for afiording access to said pipes,substantially as and for the purposes set forth.

10. A hot air furnace provided with a funnel-shaped casting supportingthe housing of a combustion chamber, fire-pot and ash-pit and forming adirector for the passage of the products of combustion to a conduit orflue directly connected with an internal vertical off-take and areceiver for extraneous matter discharged by-a gravity fall into saidconduit or fine, substantially as and for the purposes set forth.

11. A hot air furnace provided with an exterior shell, internal casingsseparated from each other to form the walls of annular chambers orpassages, a topplate provided with inlet openings and rims orprojections adjacent thereto, a detachable cap supported in positionagainst said rims or projections, an internal smoke and gaseous productoff-take connected directly with a fine or conduit, an internal housingforming the wall of a cornbustion chamber, fire-pot and ash-pitsupported by a funnel-shaped casting, and pipes extending through saidcasting and connected with the interior of said detachable cap,substantially as and for the purposes set forth.

12. A hot air furnace provided with a pot shaped casting carried by thebase-plate, an exterior shell encircling the casting and forming thewall of an air supply reservoir, an internal casing and an ash-pit,fire-pot and combustion chamber supported by the casting and forming asmoke and gaseous product passage, and air pipes traversing the smokepassage and communicating with the air supply reservoir through theinclined and curved walls of said casting, substantially as and for thepurposes set forth.

13. A hot air furnace provided with an opeii top internal housingcomprising the wall of the combustion chamber, fire-pot and ash-pit, andthe latter having a removable false bottom and a door or doors in thewall thereof, a funnel-shaped dust collector and gaseous productdirecting device supporting in position said housing, a hot air;reservoir in the top of the furnace, an air reservoir beneath saidfunnel-shaped collector and director, air pipes projecting throngh'ihewall of said device, and means provided in the top-plate of the furnacefor admitting in a downward direction currents of cold air into theinterior of the furnace and lower reservoir, substantially as and forthe purposes set forth.

14. In a hot air furnace, a funnel-shaped dust collector and gaseousproduct director provided with radial arms having a ring, and an ash-pitsupported by said ring, substantially as and for the purposes set forth.

15. A hot air furnace provided with a funnel-shaped dustand sootcollector and gaseous product director connected with a conduit or fiueleading to an internal smoke and gaseous product flue or off-take andsupporting the housing of a combustion chamber, fire-pot and ash-pit,and means, substantially as described, for regulating or checking thedischarge of smoke and gaseous products from the combustion chamberv ina downward direction to said flue or oft-take, substantially as and forthe purposes set forth.

16. A hot air furnace provided with means. as described to permit from apoint central with respect to the internal area of the furnace of thedischarge in a downward direction of smoke and gaseous productsofcombustion to a point substantially central with respect to the area ofthe base-plate and then in an upward direction through the interior ofthe furnace off-take and the admission and conduction of cold air in adownward direction and then in an upward direction through the furnacepreparatory to the super-heating of the same and the distributionthereof, substantially as described.

In witness whereof I have hereunto set my signature in the presence oftwo subscribing witnesses.

JOHN EVANS. Witnesses:

THOMAS M. SMITH, RICHARD O. MAXWELL.

